NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   Renesis Rotors (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/renesis-rotors-29156/)

GTUs 11-23-2003 11:44 PM


Originally Posted by 75 Repu' date='Nov 23 2003, 11:05 AM
what needs to be machined?

I seconded to that inquiry.



plus how much did it cost for machining?

pengaru 11-24-2003 12:17 AM

I'm guessing they machined the apex seal grooves to run the larger (older) apex seals?



It should be possible to run the renesis seals without machining anything, but the seals for the renesis are quite pricy, for the whole kit.



Theres also some concern with the renesis seals not being able to tolerate the peripheral ports on the previous series' rotor housings. Some people have claimed there is a risk of them bending and binding up in the ports, hence why someone would want to use the previous seals which are larger, requiring machining.



Hopefully Robbomaz can clear it up for us https://www.nopistons.com/forums/pub...IR#>/smile.png

crispeed 11-24-2003 12:29 AM

I've ran 9.7 compression rotors on turbo applications without any problems. I've made close to 600rwhp and ran over 30psi with no drawbacks but only gains over the lower compression ones. Precise tuning is the key no matter what the compression is.

FikseRxSeven 11-24-2003 12:35 AM

hmmm 600 hp..... ill take his word

13BAce 11-24-2003 01:15 AM


Originally Posted by FikseRxSeven' date='Nov 23 2003, 10:35 PM
hmmm 600 hp..... ill take his word

I heard from somebody a few years ago that crispeed was doing that, but I never said anything because I was told that it was a secret. I guess I'm not special after all. https://www.nopistons.com/forums/pub...#>/biggrin.png

BigTurbo74 11-24-2003 01:56 AM


Originally Posted by crispeed' date='Nov 24 2003, 12:29 AM
I've ran 9.7 compression rotors on turbo applications without any problems. I've made close to 600rwhp and ran over 30psi with no drawbacks but only gains over the lower compression ones. Precise tuning is the key no matter what the compression is.

can u tell us the setup you were using??? is it the engine that you ran a 9.2 in??? unless it's a secret https://www.nopistons.com/forums/pub...R#>/unsure.png

13BAce 11-24-2003 02:13 AM


Originally Posted by BigTurbo74' date='Nov 23 2003, 11:56 PM
can u tell us the setup you were using??? is it the engine that you ran a 9.2 in??? unless it's a secret https://www.nopistons.com/forums/pub...R#>/unsure.png

http://www.fullboost.com.au/cars/featureca...hris_intro.html

I think he's now running an FD motor with a Cosmo intake manifold.

Robbomaz 11-24-2003 05:38 AM


Originally Posted by BigTurbo74' date='Nov 24 2003, 06:10 AM
ok i have a question, when using lower compression rotors for a high hp application, it is easy to use healthy amounts of boost to up your power. now with the higher compression rotors you can still boost the engine but it will be at a limit and tuning must be very precise correct? now what i want to know is which method is better in the sense of flat out making high power? low comp/high boost or high comp/low boost?

How to put it simply (& avoid typing heaps! https://www.nopistons.com/forums/pub...IR )

There is a mechanical limit to chamber pressure, which is the boost + CR.

Now heres some broad generalisations:

High CR/lower boost will show more midrange and equal power to a low CR/high boost setup. Off boost performance and the spool-up will be significantly better.

So what? Most turbo cars (even ours!) spend over 70% of their time off boost is why!



For flat out (drag, circuit etc) the flat response from a low CR is not an issue as the car spends 90% of it's time at WOT.



The difficulty (if it can be called that) is the tune must be far more precise on the high CR unit. But like crispeed said, the tune should be right no matter what.

My 20B Cosmo for example is richer and more retarded than our Fd racer. I want the 20B to go a few years between rebuilds, the FD gets a fresh engine every season.

Robbomaz 11-24-2003 05:47 AM


Originally Posted by pengaru' date='Nov 24 2003, 02:17 PM
I'm guessing they machined the apex seal grooves to run the larger (older) apex seals?



It should be possible to run the renesis seals without machining anything, but the seals for the renesis are quite pricy, for the whole kit.



Theres also some concern with the renesis seals not being able to tolerate the peripheral ports on the previous series' rotor housings. Some people have claimed there is a risk of them bending and binding up in the ports, hence why someone would want to use the previous seals which are larger, requiring machining.



Hopefully Robbomaz can clear it up for us https://www.nopistons.com/forums/pub...IR#>/smile.png

We probably could have used the renesis seals, but this was not something I could be definate about, given that we knew the seals did not cross a port as designed.



The renesis seals may well be fine but that was not a risk I wanted to take with this guys motor. He is an unsponsored racer (apart from our discount price https://www.nopistons.com/forums/pub...IR ) and needed a season + package so it was decided to machine the grooves to take proven seals. I'm sure someone will use the new seal in an old motor soon. I believe the gas edge is better sealing on renesis seals.

andynogo 11-24-2003 07:50 PM

Yes but the renesis seals are about half the height of the older seals, so will likely flex more when encountering the exhaust port in a pre-renesis motor.



Flex = bang!


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